I. Field of the Invention
The present invention relates to a rigid abdominal pad for a lumbar/sacral support to decrease the risk of back or spinal injury arising from lifting heavy objects, for example.
II. Description of the Prior Art
Musculoskeletal disorders are some of the more common impairments in both male and female populations. Disorders of the back and spine make up the largest fraction of the total category of musculo-skeletal problems. These conditions also rank first in cost outlays by industry. As a result, musculoskeletal disorders are among the most important disease categories affecting both industrial economies and various U.S. health reimbursement systems.
Indeed, low back pain is often believed to be one of the most common causes of absence from work in today's work force. It has also been estimated that about 20% of all occupational injuries in the U.S. are back related and that about 70-80% of the world's population will have suffered this type of orthopedic problem sometime during their life.
Additional difficulties arise when the related cost of back problems occur. Taking into account the average hospital cost, salary compensation, disability payments and replacement expenses, the back ache poses itself as a destructive pathology in the American workplace. It has been estimated that such costs may be as high as $30 billion annually.
The etiology of back injuries are directly related to muscular-skeletal disuse and misuse syndromes, as well as the incidence of unpreventable trauma. Chronic stress and strain demonstrated over a period of years account for many degenerative related back pathologies. The results of general muscular-skeletal disuse and misuse manifest the eventual disruption of the vertebral bodies resulting in micro-fractures, herniation, and disk degeneration.
Certain of the risks of lower back pain and/or injury may be minimized by selecting appropriate individuals to perform the task. It is also desirable to provide education and training in the proper methods of lifting. However, these approaches are not widespread or properly followed in many instances and thus do not add much to the prevention of industrial back injuries.
A more promising approach to reducing the risk of lower back injuries has come from the recognition that the human trunk or torso functions similarly to a resilient cylinder which can be made to stiffen or relax. As the cylinder stiffens, the stress on any given portion of the cylinder tends to spread out over the whole of the cylinder thereby reducing the stress at the given location. This situation similarly occurs in the human body, whereby as the intra-abdominal pressure (IAP) of the torso increases, the load on the human trunk is transferred from the back to the abdominal cavity. Specifically, (1) the spine is essentially a segmented column supported by the paraspinal musculature which attaches anteriorly to both the thoracic and abdominal cavities; (2) actions of the muscles through movement creates a rigid mass with the capability of transferring forces from the spine to the trunk; (3) contraction of the trunk musculature creates a system of pressurized rigid chambers in the thorax and abdominal cavities which are filled with air and a semi-fluid mass, respectively; and (4) IAP increases with the strain of muscle contraction.
It has been known to artificially induce some increase in IAP by compressing the abdomen with a belt or corset tightened about the waist. An example is the well-known weight-lifters belt which is generally comprised of a leather strap with a widened portion adapted to be situated over the wearer's back and across the spine. Another device promoted widely for industry is known as the CompVest back support available from Comp Equipment Corporation, 1473 Energy Park Drive, St. Paul, MN 55108. The CompVest device is made of a light weight nylon mesh with anterior velcro closures and has a front portion adapted to be situated between the ribs and the pelvic bone and a rear portion adapted to overlie the back and spine and the upper buttocks.
With the conventional weight lifters belt or the CompVest device, tightening of the device about the waist has been suggested to increase IAP thus shifting some of the load from the spine to the abdominal cavity. However, even with the increase in IAP induced by compressing the waist, the stresses associated with lifting even normally encountered loads is believed to require more support than is provided by the belt or vest device. Specifically, it is believed that the spine and the trunk musculature must still bear an inordinate load thereby not sufficiently reducing risk of lower back pain and/or injury during normal lifting procedures. Similarly, the musculature is thus strained any may fatigue or become injured.
Some belts or corsets have also been utilized to force proper posture for lifting. For example, a conventional weight lifters belt does not Pat. No. 4,543,370 proposes to modify such a belt by equipping it with a wide front portion which contacts or overlies the sternal half of the tenth rib and the anterior portion of the iliac cost in the pelvis. The wide front portion acts to restrict excessive forward bending and thus promotes proper lifting posture. While forcing the abdomen to remain substantially straight, the approach suggested by Welsh to accomplish this result is not believed to be desirable. Contact by the front of the belt with the bony prominences about the abdomen in generally uncomfortable and may cause injury or lead users to stop wearing the belt. Further, that contact may lead to loss of consistent pressure distribution within the abdominal cavity. Such contact also limits the extent to which the front of the belt may be tightened against the abdomen. Hence, to promote proper posture as suggested in the Welsh patent may reduce the benefit available with a conventional weight lifters belt. For example, to obtain desired increases in IAP may require that the musculature absorb even more of the load then may be required of conventional weight lifters belts. Thus, in view of the state of the art, there is definitely a present need for a device which can increase intra-abdominal pressure and promote proper posture while reducing risk of injury or fatigue.